The present invention relates to conveying and, in particular, to the conveying of pans of food products through a controlled environment.
It is conventional to conduct products, such as foodstuffs, for example, through a chamber wherein the environment (temperature, humidity, etc.) is controlled. In the case of bakery or dough products such a chamber may comprise a proofer wherein the products are conveyed for an extended period upon a helically arranged conveyor. Commonly, the conveyor comprises an endless chain having wheels which travel along a guide track. However, the wheels require lubrication, which raises the possibility of lubricant falling into and contaminating the food being conveyed. Also, the lubricant can retain dust and other foreign particles, thus creating unsanitary conditions. Unsanitary conditions are exacerbated by the reluctance to wash the conveyor since washing removes the needed lubricant.
In a conveyor system disclosed in U.S. Pat. No 3,450,250 issued to Frisk on June 17, 1969, a conveyor chain is proposed which contains no wheels or wheel bearings. That proposal involves positioning stationary support rails beneath metal carriers which are mounted on the metal chain by means of metal brackets. The rails are covered with strips of plastic material. In regions where the conveyor changes direction, a curved stationary guide is provided which is positioned to contact and laterally stabilize the metal chain. The guide is covered by a plastic strip.
It would be desirable to provide a conveyor which avoids the need for support wheels and wheel bearings. However, it is also desirable to minimize friction without requiring frequent replacement of the major components, such as the chain. Despite any advantages which may have been achieved by Frisk's plastic-to-metal sliding contact, substantial room for improvement remains.
It is, therefore, an object to minimize or obviate disadvantages previously present in the art.
A further object is to eliminate the need to apply lubricant to a conveyor.
Another object is to provide a conveyor which generates minimal friction during travel and yet is relatively inexpensive to maintain.
A further object is to provide a conveyor in which the carriers are securely mounted to the chain but are quickly and easily replaceable.
Another object is to provide a conveyor in which the chain is slidably supported by means of plastic-to-plastic surface contact.
An additional object is to provide a conveyor which is supported against rising as it changes direction.
A further object is to provide an easily cleanable conveyor having rounded corners which can be washed without impairing the conveyor's performance.